我正在 Swift 3 - xcode 8 中做一个项目，我正在尝试使用核心数据在数据库表“users”中保存和显示一些图像”。 此图像是他个人资料中的用户照片。

现在我已经设法保存字符串并从核心数据中显示它们，但我在处理图像时遇到了问题。

这是我目前所拥有的:

将 USERS 添加到核心数据中

func addUser() {
    let app = UIApplication.shared.delegate as! AppDelegate
    let context = app.persistentContainer.viewContext
    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users")
    request.returnsObjectsAsFaults = false

    let newUser = NSEntityDescription.insertNewObject(forEntityName: "Users", into: context)

    if (firstName.text == "" && lastName.text == "" && contact.text == "" && email.text == "") { //if we have a user profile delete it
        deleteUser()
    } else { // add a new user profile
        newUser.setValue(firstName.text, forKey: "firstName")
        newUser.setValue(lastName.text, forKey: "lastName")
        newUser.setValue(contact.text, forKey: "contact")
        newUser.setValue(email.text, forKey: "email")

        //newUser.setValue(imageView.image, forKey: "photo")
        //let imgUrl = UIImagePickerControllerReferenceURL as! NSURL
        let img = UIImage(named: "f.png")
        let imgData = UIImageJPEGRepresentation(img!, 1)

        newUser.setValue(imgData, forKey: "photo")

        print ("Data added in Users")
    }
    do {
        try context.save()
        //print("saved!!!")
        Alert.show(title: "Success", message: "Profile Saved", vc: self)
    } catch {
       // print ("Error")
        Alert.show(title: "Error", message: "Profile not Saved", vc: self)
    }
}

显示用户来自核心数据

func showUser() {
    let app = UIApplication.shared.delegate as! AppDelegate
    let context = app.persistentContainer.viewContext
    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users")

    request.returnsObjectsAsFaults = false

    do {
        let results = try context.fetch(request)

        if results.count > 0 {
            print("Profile: Data Found:")
            for result in results as! [NSManagedObject] {
               if let firstNameinData = result.value(forKey: "firstName") as? String{
                    firstName.text = firstNameinData
                    print(firstNameinData)
                }

                if let lastNameinData = result.value(forKey: "lastName") as? String{
                    lastName.text = lastNameinData
                    print(lastNameinData)
                }

                if let contactinData = result.value(forKey: "contact") as? String{
                    contact.text = contactinData
                    print(contactinData)
                }

                if let emailinData = result.value(forKey: "email") as? String{
                    email.text = emailinData
                    print(emailinData)
                }

                if let photoinData = result.value(forKey: "photo") as? UIImage{
                    imageView.image = photoinData
                }
            }
        } else {  // if there is not a user profile
            firstName.text = ""
            lastName.text = ""
            contact.text = ""
            email.text = ""
            print("Profile : No data found")
        }
        //print("Loaded!!!")
    } catch {
        print ("Error Loading")
    }
}

我无法显示我保存的图像。 你有什么建议吗？

编辑:Xcode 给我这条消息“与 assetsd 的连接被中断或 assetsd 死亡”

最佳答案

Users 的属性 photo 是 (NS)Data，正如您在那里所做的那样，将

UIImage 到 NSData。

let img = UIImage(named: "f.png")
let imgData = UIImageJPEGRepresentation(img!, 1)
newUser.setValue(imgData, forKey: "photo")

当您检索信息时，您所做的就像 photo 是一个 UIImage 对象:

if let photoinData = result.value(forKey: "photo") as? UIImage{
    imageView.image = photoinData
}

根据前面几行，这是不合逻辑的。它应该是这样的:

if let imageData = result.value(forKey: "photo") as? NSData {
    if let image = UIImage(data:imageData) as? UIImage {
        imageView.image = image
    }
}

注意:我不会说 Swift，因此建议的代码可能无法编译，但您应该了解哪里出了问题以及需要做什么。

关于swift - 如何保存和显示带有核心数据的图像 - swift 3，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/40342196/